People seem to enjoy dark patterns, so here is one with some circles.
Source Atle Mo
From a drawing in 'Two Women in the Klondike', Mary Hitchcock, 1899.
Source Firkin
Pattern Background, Texture, Photoshop Structure style CC0 texture.
Source Darkmoon1968
One more sharp little tile for you. Subtle circles this time.
Source Blunia
In the spirit of WWDC 2011, here is a dark iOS inspired linen pattern.
Source Atle Mo
To get the tile this is based on, select the rectangle in Inkscape and use shift-alt-i.
Source Firkin
Abstract Tiled Background Extended 8
Source GDJ
Remixed from a drawing in 'Canadian forest industries July-December', 1915
Source Firkin
A dark pattern made out of 3×3 circles and a 1px shadow. This works well as a carbon texture or background.
Source Atle Mo
Prismatic Abstract Geometric Background 3
Source GDJ
Seamless , tileable CC-0 texture. Created by my own, feel free to use wherever you want!
Source Linolafett
A free green background pattern with a pattern of rhombuses on a seamless texture. Feel free to use it as a tiled background image on your web site.
Source V. Hartikainen
The base gradient edited so now more details are rendered.
Source Lazur URH